The LBNF Beamline Alfons Weber University of Oxford
The LBNF Beamline Alfons Weber (University of Oxford & STFC/RAL) European Neutrino Meeting LBNF/DUNE CERN, CH 7 -8 April 2016
Content • Overview - Experimental Setup • Beamline - Primary beamline - Target Hall - Decay Pipe - Absorber • Neutrino Beam optimisation (preliminary!) - target, horn, p beam • Summary 2 7 -Apr-2016 Alfons Weber | The LBNF Beamline
LBNF SURF Fermilab 3 7 -Apr-2016 Alfons Weber | The LBNF Beamline
The Near Facilities RF To SU 4 7 -Apr-2016 Alfons Weber | The LBNF Beamline
How to make a neutrino beam Nu. MI 5 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Primary Beam Line Protons/cycle @60 -120 Ge. V 1. 2 MW era: 7. 5 x 1013 2. 4 MW era: (1. 5 -2. 0)x 1014 0. 7 – 1. 2 sec rep. rate 3 D model of the primary proton beamline Beam size at target tunable between 1. 0 -4. 0 mm The beam lattice • 25 dipoles • 21 quadrupoles • 23 correctors • 6 kickers • 3 Lambertsons • 1 C magnet MI-10 6 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Target Hall DECAY PIPE UPSTREAM WINDOW Cooling panels DECAY PIPE SNOUT Design principle • flexibility • 2. 4 MW (when needed) 7 7 -Apr-2016 Alfons Weber | The LBNF Beamline Here • 2 horns • Graphite target • Air atmosphere 50 TON CRANE WORK CELL
Target and Horns 47 graphite segments, each 2 cm long Nu. MI-like (low energy) target and horns with modest modifications Strong R&D program in place 0. 2 mm spacing Two interaction lengths, 95 cm Inner Conductor of Nu. MI Horn Operated at 230 k. A for LBNF New Horn power supply needed to reduce the pulse width to 0. 8 ms. 8 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Decay Pipe • • • 9 Porous cellular concrete drainage layer 194 m long, 4 m inside diameter Helium filled double-wall decay pipe, 20 cm annular gap 5. 6 m thick concrete shielding It collects ~30% of the beam power, removed by an air cooling system 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Hadron Absorber Hall Designed for 2. 4 MW Cooling • Core: water • Shielding: forced air Modular design Core blocks replaceable (each 1 ft thick) Muon Alcove Muon Shielding (steel) Beam 10 7 -Apr-2016 Alfons Weber | The LBNF Beamline Bea m
Instrumentation • Beam instrumentation is essential safety and physics • Target/Absorber - Hadron/muon Monitor - Beam Position/Profile Monitor - Info 2 nd beam alignment - Current Monitor horns & target 11 • Primary Beamline 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Neutrino Production System • Original (CDR, CD 1 R) • Optimised (under study for CD 2) - 2 horns (Nu. MI-like) - 3 horns (new design) - 1 m target - ~2 m target • Graphite fins or rod • Beryllium spheres - Target chase atmosphere • Air as default - Hadron Absorber • Sculptured core blocks 12 7 -Apr-2016 Alfons Weber | The LBNF Beamline - Target chase atmosphere • N 2 or He or air - Hadron Absorber • simplified
Beam Optimisation • Neutrino flux and spectrum and detector define physics reach - Optimize neutrino flux for the physics • Handles - Proton beam power and energy - Target material and shape - Focussing elements (horns) - Decay volume • Use genetic algorithm to optimize CP-sensitivity - Choose parameters at random - Evaluate fitness (CP-sensitivity) - Pick best configurations and mate them - Generate new configuration derived from parent configuration 13 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Horn Parameters Optimisation with 3 horn system 14 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Beam Optimization (preliminary) Best fitness: 1. 97 Compared to 1. 47 reference • CP Fitness: fraction of 3σ CP coverage • Significant number of iterations • Each with O(100 k) events 15 7 -Apr-2016 Alfons Weber | The LBNF Beamline
16 Final Optimum Parameter Lower Lim Upper Lim Unit Early Optimum Horn A: LA 1000 4500 mm 2612 2815 Horn A: F 1 A 1 99 % 81 65 Horn A: r 1 A 20 50 mm 38 34 Horn A: r 2 A 20 200 mm 109 145 Horn A r. OCA 200 650 mm 563 630 Horn B: LB 2000 4500 mm 2361 3229 Horn B: F 1 B 0 100 % 29 20 Horn B: F 2 B 0 100 % 18 21 Horn B: F 3 B 0 100 % 1 1 Horn B: F 4 B 0 100 % 20 22 Horn B: R 1 B 50 200 mm 163 191 Horn B: R 2 B 20 50 mm 48 47 Horn B: R 3 B 50 200 mm 189 204 Horn B: ROCB 200 650 mm 628 630 Horn. B: Z position 2000 17000 mm 4269 3637 Horn C: LC 2000 4500 mm 2723 2816 Horn C: F 1 C 0 100 % 45 36 Horn C: F 2 C 0 100 % 13 16 Horn C: F 3 C 0 100 % 1 3 Horn C: F 4 C 0 100 % 16 5 Horn C: R 1 C 50 550 mm 365 398 Horn C: R 2 C 20 50 mm 49 45 Horn C: R 3 C 50 550 mm 277 310 Horn C: ROCC 550 650 mm 637 643 Horn C: Z Position 4000 19000 mm 17440 17478 Target Length 0. 5 2. 0 m 2. 00 Beam spot size 1. 6 2. 5 mm 1. 68 1. 62 Target Fin Width 9 15 mm 12. 6 13. 4 Proton Energy 60 120 Ge. V 64 62 Horn Current 150 300 k. A 298 296 7 -Apr-2016 Alfons Weber | The LBNF Beamline Optimization Result
Parameter Scan 17 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Conclusion • Flux can be substantially improved • 3 horns, long target • Largely independent of target details 18 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Target & Hadron Absorber • Hadron Absorber and Target design are closely coupled - Larger target length • More protons interact lower peripheral energy deposition - Larger target radius • More beam “halo” protons interact lower central energy deposition 19 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Particle Flux at Absorber 20 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Hadron Absorber Energy Dep. 2 horns, short target 3 horns, long target, wings Additional neutrino production target/decay volume 1% ND neutrinos • Peak energy deposition reduced by factor 10 -20 • Simplified absorber design • Also reduced muon flux after absorber - Reduced radiological impact 21 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Simulations • Simulation are an important tool to design the LBNF facility • Beam optimisation - Define the optimal placement, shape and form of components - GEANT 4 based toolset available - FLUKA under development • Energy depositions - Need to understand cooling requirements - Based around MARS (could be GEANT or FLUKA) • Radiological impacts - High radiation environment, need to understand where radiation is produced and how to deal with activation 22 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Opportunities for Collaboration • non-DOE contribution essential • Ample opportunities depending on interest and capabilities - Design, R&D, eventual construction • Examples - Primary beam • Dipole and corrector magnets, PS, beam monitors, … - Neutrino beam • Target, instrumentation, hadron/muon monitor, shielding, cooling, horns, horn PS, remote handling, support modules, beam windows, absorber, … - Infrastructure • hot cell, cooling, atmosphere, … - Simulations • 23 Energy depositions, radiological implications, beam optimisation 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Summary • LBNF beamline - Highest power (neutrino) beam world wide • Variety of important tasks - Simulation, engineering, production - Scope from k$ to several M$ - Something for everybody - You have an idea how to contribute or take a lead? • Almost anything can be accommodated • Critical to success of LBNF/DUNE - Physics ~ flux * detector 24 7 -Apr-2016 Alfons Weber | The LBNF Beamline
The End 25
Nu. MI-style Parameter Scan 26 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Nu. MI-style Parameter Scan 27 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Nu. MI-style Parameter Scan 28 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Nu. MI-style Parameter Scan 29 7 -Apr-2016 Alfons Weber | The LBNF Beamline
Nu. MI-style Parameter Scan 30 7 -Apr-2016 Alfons Weber | The LBNF Beamline
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